YES! by all means replace the plastic quick connect control horns. I had one break in flight on an aileron, managed to get down safely. After checking the others, they all had stress fractures and it was only a matter of time (soon) before they broke. That hard plastic just doesn't hold up to the Texas heat and stress from a plane this size.
My tail section is removable (like instructions) and it's still doing fine. (haven't had any reason to remove it yet)